This invention relates to an arrangement for use in a mail sorting machine.
In general, use is made in a mail sorting machine of an installation for detecting a postal code number or a zone improvement program code described on each mail item, such as a postcard or a sealed letter. The detection is possible when other postal information pieces are scarce on the mail item except an addressee's name and address including the addressee's postal code number and when an information position of the postal code number is strictly defined on the mail item. An envelope for a sealed letter often has a window area through which the addressee's address described on the enclosed letter paper is visible. The window area is usually provided by a substantially transparent medium, such as a paraffin or cellophane film. On the window-having mail item, postal information pieces other than addressee's are often described or printed adjacent to and parallel with the window area. Accordingly, it is difficult to derive from the window-having mail item the postal information pieces described inside the window area alone or visible through the window area.
In U.S. Pat. No. 4,034,341, a device is proposed for preliminarily detecting information positions of the respective postal information pieces, deriving the postal code numbers of the addressee's addresses from the detected information positions, and sorting the mail items in accordance with the derived postal code numbers. It is difficult even with the proposed device to distinguish the postal information pieces described inside the window area from the remaining postal information pieces.